In data-transmission systems, for example, operating speeds of 200 bits per second are conventionally used in the signaling modems. Such a bit cadence can be obtained from a basic frequency of 1221 kHz, delivered by a crystal-controlled oscillator, through frequency division by K = 6105. This type of step-down ratio can be realized with combinations of binary frequency dividers, e.g. as disclosed in commonly owned U.S. Pat. No. 3,659,266; such division, however, involves a certain degree of distortion.